Optical recording medium and optical information processor

Abstract

An optical recording medium (D) includes tracks (T) extending along a spiral. The tracks (T) include a plurality of first sections (Ta) and a plurality of second sections (Tb) differing from the first sections with respect to at least one of width and depth. Each of the first sections (Ta) includes a first overlapping portion (11) in which the trailing end and other portion of the first section overlap each other in the tracking direction, the trailing end and the other portion of the first section being located in adjacent tracks. Each of the second sections (Tb) includes a similar configured second overlapping portion (12). Due to such a structure, the beam spot can be easily caused to circulate on the same track of the optical recording medium (D) during idling.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical recording medium and an optical information processing apparatus. The term “optical recording medium” as used herein refers to a recording medium whereby data can be recorded and / or reproduced using optical means, and is a general term encompassing not only strictly optical recording medium such as CD-ROM but also recording media whereby data can be rewritten by means of a magneto-optical recording system, phase change system, or the like. BACKGROUND ART [0002] An example of an optical disk is shown in FIG. 7. This disk is provided with a recording layer in which lands L and grooves G are formed in an alternating fashion along the tracking direction Tg (radial direction of the optical disk). A push-pull method, for example, is available as a method for performing tracking control in an optical disk device that uses such an optical disk. The interference of light reflected the optical disk is indispensable for underst...

AI Technical Summary

Benefits of technology

The present invention provides an optical recording medium and an optical information processing apparatus that can overcome the problems of previous optical recording media. The optical recording medium has a recording layer with a surface that is indented in cross section, and the tracks on the recording layer are formed with alternating first and second sections. The first and second sections differ in width and depth. The first and second sections have overlapping portions in the tracking direction. The optical recording medium may also have grooves and lands alternating with the grooves. The gaps between the tracks are offset from each other in the track direction. The optical information processing apparatus includes an optical head, an optical detector, and a push-pull signal generator. The apparatus also includes a first and second signal processor for generating tracking error signals. The controller performs tracking control based on the first and second tracking error signals. The optical recording medium and the optical information processing apparatus can improve the performance and reliability of optical recording devices.

Problems solved by technology

It becomes difficult to detect a tracking error by the above-mentioned method when the track pitch of the optical disk is smaller than the limit track pitch described above.

The control of continuous writing while changing the writing-target tracks in this manner is not easy, and its implementation is difficult.

In order to form the grooves Gd, Gt by a depicting method that uses an electron beam in the manufacture of the optical disk, two electron beams must be used, so the optical disk is also difficult to manufacture.

Firstly, it is not easy to perform control whereby the optical head is held facing the same track during idle time in which no data are written or read.

Consequently, when the optical head attempts to find the number of traversed tracks by counting the number of zero points in the tracking error signal during a seek operation for moving the optical head to a position opposite the target track, counting errors can easily occur due to erroneous counting of the sudden change in the tracking error signal described above.

Thirdly, the sensitivity with which the tracking error is detected is by no means high, and it is difficult to perform highly accurate tracking control on the basis of the tracking error signal.

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